Preheat the oven to 325F.
Line a baking sheet with parchment paper.
In a mixing bowl sift flour and salt, set aside.
Using stand or hand mixer whisk butter, granulated sugar, and vanilla. Whisk on a medium heat for about 1 minute.
Add hazelnuts, give it a stir. Add flour and beat until dough turns into a large clumps.
Grab a tablespoon of cookie dough and roll it between your hand, to make 1 inch ball. Place cookie balls on baking sheet by gently pressing on them to make sure they will stay still in place, about 1 inch apart.
Bake for 20-25 minutes or until the top are lightly colored and bottom of the cookies are light brown. Let them cool completely.
Sprinkle them with icing sugar. You can give them away as a Christmas gift, or just enjoy these Hazelnut Cookies aka Russian Tea Cakes with a hot cup of coffee. Enjoy! :D